Welded steel articles bonded by a steel alloy

ABSTRACT

Alloy steel welding wire is disclosed as being suitable for welding steels having the composition 0.18 to 0.30 percent carbon, 7.0 to 9 percent nickel, 3.5 to 4.5 percent cobalt, 0.35 to 1.10 percent each of the chromium and molybdenum, 0.10 to 0.35 percent manganese, 0.6 to 0.12 percent vanadium, up to 0.1 percent silicon, up to 0.010 percent each of sulfur and phosphorus, balance iron except for extraneous impurities within commercial tolerances. The alloy steel welding wire has the composition of 0.15 to 0.20 percent carbon, 7.0 to 8.0 percent nickel, 3.0 to 5.0 percent cobalt, 0.5 to 1.0 percent chromium, 0.8 to 1.1 percent molybdenum, 0.4 to 1.25 percent manganese, 0.10 to 0.50 percent silicon, up to 0.1 percent vanadium, up to 0.015 percent each of phosphorus and sulfur, up to 0.05 percent aluminum, up to 0.05 percent of metal of the group titanium and zirconium, balance iron except for impurities within commercial tolerances.

United States Patent Ries et a1.

[ Feb. 8, 1972 [54] WELDED STEEL ARTICLES BONDED BY A STEEL ALLOY 1966, abandoned.

[52] U.S. Cl ..29/ 196.1 [51] ...B32b 15/00 [58] ....29/196.l

[56] References Cited UNITED STATES PATENTS 2,770,030 11/1956 Carpenter ..29/196.1

3,290,128 12/ 1966 Mangannello ..29/ 196.1

Primary Examiner-Byland Bizot Attorney-Ward, McElhannon, Brooks & Fitzpatrick [57] ABSTRACT Alloy steel welding wire is disclosed as being suitable for welding steels having the composition 0.18 to 0.30 percent carbon, 7.0 to 9 percent nickel, 3.5 to 4.5 percent cobalt, 0.35 to 1.10 percent each of the chromium and molybdenum, 0.10 to 0.35 percent manganese, 0.6 to 0.12 percent vanadium, up to 0.1 percent silicon, up to 0.010 percent each of sulfur and phosphorus, balance iron except for extraneous impurities within commercial tolerances. The alloy steel welding wire has the composition of 0. 1 5 to 0.20 percent carbon, 7.0 to 8.0 percent nickel, 3.0 to 5.0 percent cobalt, 0.5 to 1.0 percent chromium, 0.8 to 1.1 percent molybdenum, 0.4 to 1.25 percent manganese, 0.10 to 0.50 percent silicon, up to 0.1 percent vanadium, up to 0.015 percent each of phosphorus and sulfur, up to 0.05 percent aluminum, up to 0.05 percent of metal of the group titanium and zirconium, balance iron except for impurities within commercial tolerances.

2 Claims, No Drawings WELDED STEEL ARTICLES BONDED BY A STEEL ALLOY This is a continuation-in-part of copending application Ser. No. 525,348, filed Feb. 7, 1966 (now abandoned).

This invention pertains to a consumable, ferritic, alloy steel welding wire of novel composition for electric arc welding and to welded articles thereof.

The welding wire of the invention is particularly adapted to the joining by welding of workpieces, such as plates, sheets, pipe, forgings, etc., made of corrosion-resistant, alloy steels known as HP 9-4-25 and HP 9-4-20 Cr, Mo having compositions within the ranges of: 0.30 percent carbon, 7.0-9 percent nickel, 3.5-4.5 percent cobalt, 0.35-1.10 percent each of chromium and molybdenum, 0.10-0.35 percent manganese, 0.06-0.12 percent vanadium, up to 0.1 silicon, up to 0.010 percent each of sulfur and phosphorus, balance iron except for extraneous impurities within commercial tolerances. These steels as hot-worked, normalized, austenitized, quenched and tempered at about 1,000 E, are extremely tough and high-strength steels of excellent ductility, typical mechanical properties for plate of which as thus processed are: ultimate strength, 190,000 to 200,000 p.s.i.; 0.2 percent offset yield strength, 180,000 to 190,000 p.s.i.; tensile elongation in 1 inch, 16 percent; reduction in area, 60 percent and Charpy V notch impact strength, 35 to 55 foot-pounds at 70 F. and 30 to 40 at 80 F. These steels and their processing and heat treatment, are covered by US. Pat. No. 3,366,471, assigned to the assignee of the instant application. These steels, owing to their high strength and touglmess, are particularly adapted for use in large, unfired, pressure vessels subjected in use to high stresses, such as hydraulic bottles, and also by reason of their corrosion resistance as well, for use in certain chemical pressure vessels and for the hulls of submersible vessels and the like, exposed to sea water.

A serious problem has been encountered, however, in so joining workpieces of these steels, such as plates, sheets and the like, by welding into a fluidtight joint and such as not to impair the strength, ductility and toughness of the steel at the weld seams in the absence of subsequent heat treatment, in-

TAB LE I.HP 79 Heat 3920563 1" plate asmuch as in the production of large pressure vessels, submersible hulls and the like, such subsequent heat treatment cannot be applied.

Such expedients as spot or pressure welding are obviously not applicable, nor is high-frequency electric current fusion welding, in the joining of heavy plates of these steels. We have found fusion welding to be most suitable wherein workpieces to be joined are welded together by means of a consumable filler or welding wire, rendered molten along the weld seam by means of a tungsten electrode arc operating in an atmosphere or blanket of an inert gas, such as argon, generally designated as gas tungsten-arc" or TIG welding.

The problem here encountered, however, resides in the provision of a consumable filler or welding wire of a composition such as to lay down a weldment that will impart a strength, toughness and ductility at least equal to that of the base metal. The obvious assumption would be that this can be accomplished by employing a filler or welding wire of the same composition as that of the base metal, but our tests have established that this is not so. This is demonstrated by the test results in the following Tables 1 and I] wherein filler wire of the same composition as the base metal was employed in T16 welding of l-inch and r-inch plates of the HP 9-4-25 steel, and the Charpy V notch (CVN) values detemiined in the base metal and in the weld metal, each at 70 and -80 F. These examples show that the weld metal toughness as evaluated by Charpy V notch impact testing is substantially below that of the base metal and does not meet a desired footpound impact value even at room temperature of F.

Data presented in Table 111 below shown that a filler wire of a composition similar to that of the HP 9-4-25 base plate material with the exception of a higher manganese (0.46 percent) and silicon (0.23 percent) develops properties as deposited in which the Charpy V notch properties at 70 F. are higher than those of the wrought heat-treated, quenched and tempered baseplate although the impact values at F. are almost identical. The yield strength of the as-deposited weld metal is, however, significantly lower than that of the baseplate with, however, a higher tensile strength for the weld metal as compared with that of the baseplate.

Composition-B ase plate and tiller wire C Mn P S Si Ni Cr Mo V Co .28 .29 .005 .005 .10 8.26 .53 .47 .16 3.82 Same as above Temp., F. CVN, ft. lb.

Charpy V notch impact:

Base Metal 1 gg 50/ Weld metal as deposited gg 1 Oil quenched from 1,550 F. and double tempered at 1,000 F.

TABLE II.-HP 92 Heat V173 16' plate TIG weld-Single U groove Welded with base plate material as is x $22 sq. sheared strips CompositionBase plate and filler wire 0 Mn P S Si Ni Cr Mo V 00 mix 3:23;; --t;...-.?. .i-J... Tomp., F. CVN, ft. lb.

Charpy V notch impact:

Weld metal gg Base metal I u: ;8

1 Oil quenched from 1,550 F. and double tempered at 1,000 F.

TABLE III.HP 161 Heat 3920874 1 Plate TIG weld-single U groove CompositionBase plate, filler wire and weldment Mn P S Si Ni Or Mo V 00 Base plate (Ht 3920874) .28 .20 .005 .008 .02 8.33 .49 .49 .11 4 05 Filler wire (3931006) 26 46 00B 006 23 8. 05 62 08 4: 0B Weldment (as deposited) .25 .41 .22 7.90 .49 .53 .09 4.01

Temp. F. CVN, ft. lb. Charpy V notch impact:

Base plate 1 ;8 g2 g2 I43 Weld metal- 35135 Elong., per- Red. area, Y.S., k.s.i. U'IS, k.s.i. cent in 1 inch percent Tensile properties:

Base plate 1 193. 5 207. 5 13.0 58. 5 Weld metal. 178.6 218. 5 15. 0 40. 1

1 Oil quenched and double tempered at 1,000 F. Tested in transverse direction.

Our further investigations of the gas tungsten-arc welding of HP 9-4-25 steel of the above composition, led to the development of a consumable alloy steel welding wire which was modified with respect to carbon, manganese, silicon, chromium, molybdenum and vanadium as compared to the composition ranges for these elements, respectively, of the HP 9-4-25 base metal. The compositions thus found to impart the desired characteristics are as follows:

Tables IV, V and V1, show Charpy V notch impact values for the as-deposited weld metal appreciably in excess of that of the heat treated (quenched and tempered) base metal. This is also true for the tensile properties in these tables as well as in Table VI] which exhibit yield and tensile strength for undiluted asadeposited weld metal equal to or greater than those for the baseplate.

Experimental filler wire heats melted within the above- C Mn P S Si Ni Cr Mo V Co Bal.

Maximurn.

2 Preferably .90/ 1.10.

Up to 0.10.

Welding test results similar to those of Tables [-11], inc., are given in the following Tables IV, V, VI and VI] to demonstrate the improved results thereover obtained by the use of filler or welding wires having compositions within the welding alloy 40 range of the present invention as above set forth.

I TABLE IV.HP

Heat 3920874 1" plate TIG weld-single U groove Welded using .125" diameter wire, product of Heat 3888697 stated composition range of this invention are noted below in Table Vlll: I

1. Carbon should be no higher than 0.02 percent and preferably somewhat below this (0. 15-020 percent).

2. The increased manganese and silicon, as compared to the Composition-base plate, filler wire and weldment 0 Mn P S Si Ni Cr Mo V 00 Base Plate (3920874) 2S 20 005 008 02 8. 33 49 49 11 4. 05 Filler wire (3888697)---" 19 1. 14 008 005 16 7. 20 99 93 09 4. 72 Weldment (as deposited) 18 1. 10 12 8. 0 94 98 09 4. 60

Charpy V notch impact: 1emp., F. CVN, ft. lb.

Base plate 1 5g g1 Weld metal gg 53 Elong., Y.S., UIS, percent Red area, Tensile properties: k.s.i. k.s.i. in 1 inch percent Base plate 1 193. 5 207. 5 13.0 58. 5 Weld metal 202. 3 223. 5 19. 0 59. 7

1 Oil quenched and double tempered at 1,000 F. Tested in transverse direction.

TABLE V.HP 191 Heat 3921021 1" Plate TIG weld-singlc U groove Welded using .062 diameter wire, product of Heat 3888723 Compositionbase plate, filler wire and weldment 3,640,690 ...5 6 TABLE V.HP l9l -Cominued Heat 3921021 1 Plate TIG weldslngle U groove Welded using .062 diameter wire, product of Heat 3888723 l Tempered 1,100 F. (4 hrs.). 2 Base tempered at 1,000 F. (2+2 hrs.). 3 Base properties from 4 X 4 forged bil1ettransverse.

TABLE VL-HP 184 Heat 3930774 2% Plate TIG Weld-single U groove Welded using .045 diameter wire, product of Heat 3888662 Composition-base plate and filler wire C Mn P S Si Ni Cr Mo V Base Plate (3930774) 32 004 .007 01 7.19 1.01 1.03 .09 3. 90 Filler wire (3888652) 21 42 008 .007 16 7. 31 1. 04 97 .025 3. 87

Temp., F. CVN, ft. lb. Clmrpy Y notch impact:

Base Plate 70 48 70 65 Weld metal 63 80 58 Elong., percent in Red. area, Tensile properties: Y.S., k.s.i. UTS, k.s.i. c percent Base plate 1 185 210 15 60 Weld Metal 203. 2 213. 6 16 1 Oil quenched and double tempered at 1,000" F.

TABLE VII.-HP 284 Heat 3931677 1' plate TIG Weld-single U groove Welded using commercially produced .062 diameter filler wire-Heat 60320 (1 ton vacuum induction heat product) Composition-base plate, filler wire and weldment C Mn P S Si Ni Cr Mo 00 V BasePlate (3931677) .17 .28 .003 .005 .02 9.10 .77 1.00 4.45 .08 FillerWire(60320) .16 .75 .003 .005 .23 7.33 .45 .94 3.34 .09 I Weldrnent (as deposited) .15 .65 .22 7.40 .54 .94 3.30 .09 Cigarpy V notch impact Base plate 1 59/65 tt.-lb. Weld metal (as deposited,

undiluted) 63/63 tt.-lb.

Elong.,

percentage Red. area, Y.S. k.s.i. UTS, k.s.i. in 1 inch percentage Tensile Properties:

Base plate 1 185. 4 198. 6 18. 0 69. 0 Weld metal (as deposited,

undiluted) 186. 7 207. 2 17.0 59. 3

1 Quenched and tempered base plate tempered at 1,000/1,025 F.4 hrs. at temperatur e TABLE VIII Heat 0 Mn P S Si Ni Cr Mo V 00 With respect to the above compositions the following points are to be emphasized:

baseplate composition, serves to enhance the usability of the vanadium content will be beneficial if stress-rclieving is filler wire and to provide suitable deoxidation for the molten required for certain applications after welding. weld metal during deposition. Also, in this regard, small 4. Minor amounts of titanium and zirconium may be added amounts of aluminum, i.e., up to about 0.05 max., serve to act 4. up to about 0.05 max.) to improve toughness. as a deoxidizer and reduce porosity of the weldment. What is claimed is:

3. No specific effects have been observed with regard to the l. A welded article comprising base metal components vanadium levels noted. It is considered, however, that a lower made of an alloy steel consisting essentially of about 0. l8 to 0.30 percent carbon, 7 to 9 percent nickel, 3.5 to 4.5 percent cobalt, 0.35 to 1.10 percent each of chromium and molybdenum, 0.1 to 0.35 manganese, up to 0.12 percent vanadium, up to 0.1 percent silicon, and the balance substantially all iron, said base metal components being welded together by an alloy consisting essentially of about 0.15 to 0.20 percent carbon, 7.0 to 8.0 percent nickel, 3.0 to 5.0 percent cobalt, 0.5 to 1.0 percent chromium, 0.8 to 1.1 percent molybdenum, 0.4 to 1.25 percent manganese, 0.10 to 0.50 percent silicon, up to 0.1 percent vanadium, up to 0.015 percent each of phosphorus and sulfur, up to 0.05 percent of metal of the group titanium and zirconium, balance iron except for impurities within commercial tolerances.

2. A welded article comprising base metal components made of alloy steel consisting essentially of about, 0.18 to 0.30 percent carbon, 7 to 9 percent nickel, 3.5 to 4.5 percent cobalt, 0.35 to 1.1 percent of each of chromium and molybdenum, 0.1 to 0.35 percent manganese, up to 0.12 percent vanadium, up to 0.1 percent silicon, and the balance iron, said base metal components being welded together by an alloy consisting essentially of about, 0.15 to 0.2 percent carbon, 7 to 8 percent nickel, 3.0 to 3.5 percent cobalt, 0.5 to 1.0 percent chromium, 0.9 to 1.1 percent molybdenum, 0.15 to 0.50 percent silicon, up to 0.1 vanadium, up to 0.015 percent each of phosphorus and sulfur, up to 0.05 percent aluminum, up to 0.05 percent of metal of the group titanium and zirconium, balance iron, said article having in the welded portion, yield and ultimate strengths of at least and 200 k .p.s.i., respectively, a tensile elongation in 1 inch of at least 13 percent, and a Charpy V notch impact strength of at least 50 foot-pounds at 70F. 

2. A welded article comprising base metal components made of an alloy steel consisting essentially of about, 0.18 to 0.30 percent carbon, 7 to 9 percent nickel, 3.5 to 4.5 percent cobalt, 0.35 to 1.1 percent of each of chromium and molybdenum, 0.1 to 0.35 percent manganese, up to 0.12 percent vanadium, up to 0.1 percent silicon, and the balance iron, said base metal components being welded together by an alloy consisting essentially of about, 0.15 to 0.2 percent carbon, 7 to 8 percent nickel, 3.0 to 3.5 percent cobalt, 0.5 to 1.0 percent chromium, 0.9 to 1.1 percent molybdenum, 0.15 to 0.50 percent silicon, up to 0.1 percent vanadium, up to 0.015 percent each of phosphorus and sulfur, up to 0.05 percent aluminum, up to 0.05 percent of metal of the group titanium and zirconium, balance iron, said article having in the welded portion, yield and ultimate strengths of at least 185 and 200 k.p.s.i., respectively, a tensile elongation in 1 inch of at least 13 percent, and a Charpy ''''V'''' notch impact strength of at least 50 foot-pounds at 70*F. 